More Carnage in the Rain, For my buddy Greg who asked nicely

Please tell what happened and how it might have been avoided. Names should be ommitted. This forum should help others learn from mistakes that caused or nearly caused a mishap.
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Jim
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More Carnage in the Rain, For my buddy Greg who asked nicely

Post by Jim » Sun Jan 10, 2016 9:09 pm

For those who have not flown a wet Mylar wing, a word of caution.

The Monday after Christmas, we were not expecting rain, with only a 10% chance forecast. Long story short, it drizzled on us, heaviest as we approached for landing.

As a fellow pilot put it afterward, expect your glider's stall speed to increase by at least 5MPH. Expecting is one thing, experiencing it is quite another. Speaking only for myself, I was shocked by the difference in the flight characteristics of my glider. As I circled down, at speeds between 30 and 40MPH, the RX3.5 had a tendency to pitch the nose down and several times I felt I was free-falling. With little or no wind, I flared a little early and ended up sailing through the control frame in a hard whack. I didn't feel any change in speed or trajectory. No damage, slightly jammed thumb.

The point being, gliders with plastic sails fly differently when wet. I'll leave the technical explanation to more capable hands.

A tip I received from Kraig Coomber: some comp pilots put a light coat of dish washing liquid on the leading edge of a Mylar sail to break the surface tension and allow the water to stream away more efficiently. Like de-icing for jets.

For my part, I'll be more careful about choosing days to fly with rain in the forecast.

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JD
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Post by JD » Mon Jan 11, 2016 9:45 am

I have an acquaintance in Norway who recently was caught in the rain on his Litespeed. Typically his landings are very good. His video illustrates how the stall speed increases and the glider just drops:
Wet landing: https://youtu.be/Tj2v-c2vt6k?t=1m34s
Dry landing: https://youtu.be/Tj2v-c2vt6k?t=3m42s

Some suggestions from having landing in the rain:

If you get caught in the rain please test your glider's stall characteristics at a safe altitude if you can.

Sometimes performing a fast dive into ground effect will blow enough globs of water on you top surface into smaller streams for just long enough to have a reasonable landing. It's no guarantee however.

If the rain is localized you may be able to fly out of it and land where it's dryer.

If the heavier period of rain has good lift and you can wait it out on the air that may be a viable option too.

YMMV

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BudRob
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Post by BudRob » Wed Jan 13, 2016 10:44 am

On the day Jim quotes, I was another pilot who also pounded in due to a wet sail (just before Jim). I knew the problem with wet sails but was lulled into a sense of complacency when the pilot that landed ahead of me reported no problems on landing. I guess he came in from a different direction and his glider was not as wet as mine and Jim's were.

The point is this: I should have tested the stall speed characteristics while I was still high and circling. Regardless of what the pilot ahead of me reported, MY glider did not fly well at slow speed and I paid the price for not checking it out myself at higher altitudes when I had the chance.

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Steve90266
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Landing in the rain

Post by Steve90266 » Fri Jan 15, 2016 3:25 pm

Good info, guys. Thanks for sharing. Thanks to your post, I'll be tuned in.
Steve Murillo

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JD
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Still More Rain Carnage

Post by JD » Mon Apr 25, 2016 9:19 pm

Cutter's Call wrote:April 25, 2016 8:23am
Report of an interesting Sunday. The early group found easy boating lift under the overcast but with rain approaching from the SW. It did sprinkle causing a bee line for the LZ. Landing conditions were a strong E. A few minor injuries and one badly damaged glider. Then the clouds passed and it was beautiful again. The second group, that waited on top, had good flights. Highest was 5,908ft.
One report I read online indicates that the pilot's Mylar sail was wet and stalled early by surprise resulting in one of these....

[youtube]http://www.youtube.com/watch?v=duhu4cnHhXg[/youtube]
This pilot did not stall test the glider at a safe altitude before attempt a landing.

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gregangsten
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the whole catastrophe

Post by gregangsten » Thu Apr 28, 2016 3:17 pm

I had to tell this story 20 times in the LZ Sunday, but I suppose I should make it 21.

The rain was flushing 3 of us to the LZ at the same time. Since I was on top, I kept my VG on full trying to give the others time to land and get away. I got involved watching Will's wild approach and forgot about my VG. When my turn came up, I headed downwind at what I thought was a good clip, turned to base and started falling like a stone in what I think was both a stall and then a side slip with my tight VG. Two wrongs make a disaster. The ground was coming up quick and as I got close I pushed out and mostly stopped my downward momentum but my left wing clipped a little tree on the berm that sent me sliding sideways across the gravel about 20 feet leaving a trail of tree.

I was prepared to flare early due to the wet Mylar effect, but I hadn't thought about it affecting my turns and was surprised by the stall and fall though I sure should have been thinking about it.

Broken downtube and stinger, two good gashes in the leading edge sail and I'm sure damage to the outboard LE, though I haven't gotten around to pulling it out yet. I wound up with just little scrapes on a knee and elbow, but the glider is pretty much a goner. At least it was old. Nearly had them saying the same thing about me.

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JD
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Re: the whole catastrophe

Post by JD » Thu Apr 28, 2016 4:18 pm

gregangsten wrote:....my left wing clipped a little tree on the berm that sent me sliding sideways across the gravel about 20 feet leaving a trail of tree.....
I found the video or at least a reasonable facsimile here...

[youtube]http://www.youtube.com/watch?v=UenSPVQe0Wo[/youtube]

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